Flexible wire rope



May '6, 1930. o. A. WIRKKALA V FLEXIBLE WIRE ROPE Filed March 26, 1928 'M 2 s a java/far:

' 0min A. Mnffdh Patented May 6, 1930 UNI-TED STATES-FATE OSCAR A. wmxKALa,

FLEXIBLE Application filed March 26, 1928.; Serial 1%. 264,702.

'My invention relates to wire rope especi'ally adapted to logging purposes and other heavy duty; also adapted to permit flexing Without undue wear or strain, while engaged 5 with a link like connection to a load for example, as'used in choker ropes and sky line logging operations.

As well known, choker ropes or cables are composed of short lengths of wire rope of 10 from approximately twenty to thirty feet, provided on one end with a hook or ferrule, intended to be secured to a slidingcollar provided on the choker rope; the loop, thus formed being passed over one or more logs and drawn closely about them and the other end of the choker, being fastened to the haul-in line by which the logsare drawn to the loading platform either through the air or over the ground.

As evident, the strain and wear on such choker ropes is severe and the wire rope used for this purpose must necessarily have a high degree of tensile strength and flexibility and at the same time be very tough and strong. A further quality of such rope must be an ability to resist the flattening strains exerted on the wire rope at the point where it passes through the sliding collar on the choker. 39 Furthermore in sky line logging operations, the logs are carried through the air,

hung by means of their chokers from carriages, which travel on the so-called slack lines which when passing over the slack portions thereof, tend to flatten the wire rope .at the running places of contact which causes the wires of the rope to crystallize and break.

Thereforethe Object 0f lIlVGIltlOIl Wires twi t dig th b which the p provide a flexible wire rope or cable, adapt 3 ed to the peculiar strains and severe duty of logging operations, which will wear long- --er, will have a higher degree of flexibility and greater strength, than the wire rope of equal size and tensile strength in present use.

A further object is to provide a wire rope or cable, adapted to successfully withstand lateral or radial compression, without deformation and the consequent premature crystallizing and breaking of the wires of which the rope is composed.

I attain my objects in a wire rope comprising a wire cable consisting of a core, an inner-most lay about such core composed of eight strands each composed of three wires, an intermediate lay about such inner-most lay, such intermediate lay composed of eight strands, each composed of seven wires, and

an exterior lay about said intermediate lay such exterior lay composed of eight. strands of nineteen Wires, the wire composing each of said strands being twisted together in the same direction, andthe twist of the strands composing the lays being twisted in the opposite direction to that of the wires composing the strands,.and the diameters of the wires composing the strands being relatively increased from the interior lay to the exterior lay, in the ratio of 7, 9 and 11 approximately. Further. details of construction and the manufacture thereof are hereinafter described with reference to the accompanying drawings, in which: I Fig. 1 shows an end view of my-wire rope and illustrates the relative arrangement and proportions of the wires, strands and lays. Fig. 2 shows a side view of my wire rope thecore and successive lays being each cut away to disclose the direction in which the wires and strands are twisted and their arrangement and. proportion and Fig. 3 shows a view similar to Fig. 2, ex'- cept that the strands and wires have been partially untwisted to further illustrate their arrangement and proportions.

With reference to theifigures my wire rope comprises a core a which may be of hemp,;in the smaller sizes, or in larger sizes, several terior lay b may be twisted.

The interiorlay '6 consists of 8 strands 0. of three .wires (2', the strands being twisted in the opposite direction to the wires composing the strands. I

The intermediate lay e consists of 8 strands f of 7 wires 57, the wires being twisted in the same direction as the wires 03, and the strands f being twisted about the interior lay b, in the same direction asthe strands f whereby the strands f will'lie closely in the sprial grooves formed by the strands b, in the exterior surface of the inner lay.

The exterior lay it is composed of 8 strands i of 19 wires j twisted in the same direction as the inner strands and wound about the lay'e, in the opposite direction to the wires 7', butin the same direction as the strandsc and f, similarly to the lay 6, about the lay b.

The wires composing the strands and f and i are each relatively larger in diameter from the interior lay outwardly and are so proportioned with respect to each other and to the numbers of wires used in each lay, that a wire rope is provided in which the breaking strain of each strand is relatively equal.

That is, the tensile strength of the wires (Z is greater per square inch of cross sectional area, than the larger wires. 1 of theintermediate lay and similarly,the tensile strength of the wires 9 per square inch of cross sectional area are greater than the still larger wires of the exterior lay.

Consequently, the breaking point of the wires and the strands will be equal, since the i smaller wires having greater longitudinal elasticity than the larger wires in proportion to their diameters, will part, at the same breaking strain as the larger wires, which do not have as great elasticity due to their lesser proportional breaking strain.

-I have found that this result will'be best obtained if the diameters of the wires of the respective lays are proportioned respectively in a definite ratio and I have found such ratio to be that of 7, 9 and 11 approximately, a

' small variation being permissible to permit wires of even diameters to be used. 7

For example, 1n an inch and a quarter w1re rope, the diameters of the wires will be them and form a substantially homogeneous rope adapted to sustain lateral compression and to support longitudinal strains as a unit.

2. A wire cable consisting of a core, an innermost lay, an ntermedlate lay and an outermost lay, the lays being composed of an equal number of strands, the strands composing the laysconsisting of a relative greater number of wires from the innermost lay outwardly in the ratio of 3, 7 and 19, and the diameters of the wires composing the strands being relatively increased from the innermost lay outwardly in-the ratio of 7,'9 and 11 approximately, the wires composing each of the strands being twisted together in the same direction and the strands of each lay being twisted in the opposite direction to that of the wires composing the strands, whereby the wires composing the strands, and the strands will lie closely together with practically no interstices between them andform a substantially homogeneous rope adapted to sustain lateral compression and to support longi-.

tudinal strains as a 'unit.-

1 OSCAR A. WIRKKALA.

.O42, .054 and .066 of an inch respectively, and

in other sizesof wire rope, such as one inch or one and one-half inch, the diameters of the wires will be in the same ratio approxi mately.

Thus I provide a rope, solidly made from the center outward, of great flexibility, adapted to resist lateral or radial pressure without deformation, anda rope which because of greater strength will permit a smaller size tothe used with the resulting saving in weight and cost of material.

I claim:

1. A wire cable consisting of a core, an innermost lay, an intermediate lay and an outermost lay, the. lays being composed of an equal number of strands, the strands composing the laysconsisting of a relative greater number of wires from the innermost lay outwardly in the, ratio of 3', 7 and 19, and the diameters of the wires composing the strands being relatively increased from the innermost lay outwardly in the ratio of 7, 9 and 11 approximately, whereby the wires composing the strands and the strands will lie closely together with practically no interstices between 

